TOWARDS ON-TIME PASSENGER HANDLING

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"Develop a thirst for knowledge - this will lead to an ability to reason, to reduce the complicated to simplicity and to make prudent decisions"

Collett E. Woolman – Principal CEO of Delta Air Lines

“Prediction is very difficult, especially if it is about the future”

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A CASE STUDY RESEARCH ON THE REQUIRED SERVICE CAPACITY

FOR AN ON-TIME PASSENGER-HANDLING PROCESS AT THE GATE

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Title Towards on-time passenger handling

Sub Title A case study research on the required service capacity for an on-time _{passenger-handling process at the gate}

Keywords Passenger-handling; gate; case study; queuing theory; KLM

Confidentiality The content of this document is confidential and may not be copied In partial fulfilment of the requirements for the degree of

Master of Science

in Transport, Infrastructure and Logistics

at Delft University of Technology, the Netherlands Student Hidde Janssen BSc

Student Number 1366734

Master Program Transport, Infrastructure and Logistics University Delft University of Technology

Company KLM Royal Dutch Airlines Version Final Thesis Report

Date May 6, 2015

Graduation Committee Prof.dr.ir. G. Lodewijks

Professor Transport Engineering and Logistics Department of Maritime and Transport Technology

Faculty of Mechanical, Maritime and Materials Engineering Dr. W.W.A. Beelaerts van Blokland

Assistant Professor Transport Engineering and Logistics Department of Maritime and Transport Technology

Faculty of Mechanical, Maritime and Materials Engineering Dr. M. Janic

Senior Researcher Planning and Design of Transport Systems Department of Transport and Planning

Faculty of Civil Engineering and Geosciences Ir. R.J. Ottens

Manager Product Development Department of Passenger Services Division of Ground Services

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PREFACE

This thesis is the last fulfilment to obtain the Master degree in Transport, Infrastructure and Logistics at Delft University of Technology in the Netherlands.

My research was not only of interest to KLM, but also one of mine. My predilection of airports, airlines and aircraft was completely fulfilled while having my research on airside of Amsterdam Airport Schiphol. I have done my best to write down what I’ve experienced, seen, learned, done and research during my graduation internship, in order to add new knowledge on what is so much underestimated: the gate process.

In the first place I would like to thank my company supervisor Richard Ottens, but also Adriaan den Heijer and Maarten Koopmans, for the opportunity to execute my graduation internship at KLM Royal Dutch Airlines. Having a sneak-peak in their company was one to do’s on my bucket list during my studies in Delft.

Furthermore, I would like to thank the team of Product Development for having me in their team, and the other colleagues of Passengers Services I had the pleasure to speak with regarding my research. A special thanks goes to Ricardo Kallendorf, for providing me with the available data after all those requests I did at his desk.

Other thanks go to my graduation committee, study mates, and friends. Special thanks go to Ginette, for all the coffee we had together discussing our graduation work. Even more special thanks go to my girlfriend, Marissa, for her unbridled support during my thesis. And last but certainly not least; my parents, as this thesis is the finale of what could not have been possible without them.

May 6th_2015,

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EXECUTIVE SUMMARY

Airline passengers want short and seamless connections, departure and arrival punctuality are therefore key. KLM is currently losing a strong position as network connector, as the operability of transfer flights is under pressure: departure punctuality is substandard. Offering attractive connections to passengers is KLM’s right of existence as 70% of its customers are transferring at their only hub: Amsterdam Airport Schiphol. Therefore, the departure punctuality should be brought back to an acceptable level.

KLM scores well on the international standard indicator for arrival punctuality, their on-time departure punctuality is however substandard: declining from 50% in 2009 to as low as 20% over 2014. One contributor to the low departure performance is the inefficient ground operation. Regarding the passenger-handling process there were some other figures raising questions. In 53% of the cases the gate process took longer than planned. The gate process is therefore the object of study.

I RESEARCH BACKGROUND

For passengers, the gate process is about waiting and boarding the aircraft. For an airline, it is much more. Most research focuses on platform processes or the boarding process only, without paying attention to other gate processes in the same area or department. Their impact has been underestimated so far. The objective of this research is to provide new knowledge on the gate process and its sub processes, in order to achieve more punctual departures of intercontinental

flights. The main research question is therefore: what operational changes are needed regarding

the gate process, in order to improve on-time passenger-handling performance?

In order to answer this question, several theories and techniques have been used: case study methodology in business research used to research the gate process from a passenger-handling perspective in a structured way, the Theory of Constraints, Critical Path Analysis and a Swim Lane Diagram to find what bottleneck held the gate process from operational excellence and Queuing theory in order to improve the current state.

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II CURRENT STATE

The current state process illustrates what happens at the gate in the real context. The analysis was focussed on what caused the gate processes to take longer than planned and what therefore was the bottleneck in the gate process that should be improved.

The analysis of the current state is executed according to the Theory of Constraints, where the gate process is rewritten as a queuing system and critical path analysis is done to check what sub processes form constraints in the gate process. By means of surveying, the process is viewed in its real life context, while scores from these observations were to be analysed in a quantitative manner.

Conclusions that have been drawn up result in five main causes that made the gate process take longer than planned:

! There are more processes than specified

! The demand for service is not the same for every flight

! The demand for service is not the same for every passenger

! Supply is not matched to variables of the demand

! The capacity model in use does not take into account passenger arrival patterns

The bottleneck of the gate process is the capacity constraint: the current performance of passenger door closed is substandard and the total gate process duration exceeds its planned time frame. Supply and demand are not matched and not all information available is taken into account for forecasting. The new objective became to design a new method of approaching the passenger handling capacity need, based on a queuing system, in order to resolve this bottleneck.

III FUTURE STATE

The design of the future state method is a redesign of the current state, with improvements based on the results of the analysis executed. This started with the selection of variables that should be taken into account in the future state gate queuing system. These are inter alia the passenger profile, as this is a predictor of the service need per passenger type, but also their arrival pattern. All together they where put in the future state gate queuing system.

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Two concepts of interest represent a probabilistic relation selected for testing by case study:

! The more high pace profile passengers on a flight, the less demand for service there is.

Therefore less service capacity is needed, relative to the average as specified.

! The more low pace profile passengers on a flight, the more demand for service there is.

Therefore more service capacity is needed, relative to the average as specified.

These concepts have been tested by means of a comparative case study between the revealing cases of KL871 to New Delhi and KL895 to Shanghai in their natural context. The results from this research are analysed in a qualitative manner. Despite the service capacity was not equal during testing, it became clear that the New Delhi flight had a higher service demand than the Shanghai flight, inter alia due to their passenger pace profile composition. The time available for the gate process is given and fixed, the demand is dependent on other variables and therefore the supply is the factor that should be elevated above others within the passenger-handling process. Unfortunately, the research cannot provide exact numbers yet, but the expected change is positive as long as the supply can be adjusted to fit the demand: there must be enough agents.

IV CONCLUSION AND RECOMMENDATIONS

Given what is considered and based on what is researched, it can be concluded that the gate process should be approached as a queuing system. This leads to better capacity estimations. Secondly, more variables should be included in the future state, as the service capacity needed in the gate queuing system is determined by more than the boarding process solely. The variables that should be taken into account are:

! The number of passengers expected

! The arrival pattern of the passengers

! The service demand of the passengers, according to passenger profile needs

This will lead to more specific calculations on individual flight basis, needed for a punctual departure of every flight.

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More research is recommended, as it is expected that there are more variables that influence the service need within the passenger handling process at the gate, such as the hand baggage passengers take on board, the length of the ineligible to board list or passengers that are known to be not 100% OK.

This whole new approach has a large impact on the current practice, but is needed to improve the performance of today. KLM is on the verge of making a decision on how to improve their departure punctuality on the short and long term; therefore several recommendations are provided for their specific operations. On the short term it is advised to hire more staff for the assignment bureau and organise improved refreshers for agents to make clear what happens why and what is the urge of on time departure. The management is advised to visit their process more on-site and respond fast and firm on everything that is not according to plan.

On the long term KLM should focus on basics right: too many processes and information are not aligned and can be improved based on what is available, instead of applying innovative technology or complete new processes. Data is in most cases available, but not used at all. On step back will eventually lead to three steps forward.

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TABLE OF

INTRODUCTION

CHAPTER 1

Airline passengers want short and seamless connections, departure and arrival punctuality are therefore key (Eurocontrol, 2005). KLM is currently losing a strong position as network connector as the operability of transfer flights is under pressure: departure punctuality is substandard. Offering attractive connections to passengers is KLM’s right of existence as 70% of its customers are transferring at their only hub: Amsterdam Airport Schiphol (KLM, 2014b; Schiphol Group, 2014a). Therefore, the departure punctuality should be brought back to an acceptable level.

KLMs scores well on the international standard indicator for arrival punctuality, for arriving

within fifteen minutes of scheduled time of arrival (A15): 85% over 2013 and almost 89% over

2014, making them the second-best respectively best performing large airline serving intercontinental routes in respect to arrival punctuality (FlightStats Inc., 2014, 2015). Their

on-time departurepunctuality (D0) is however substandard: declining from 50% in 2009 to as low as

20% over 2014 (KLM Passenger Services Support, 2014), where the target is at least 33% (Appendix C ).

figure 1.1 Departure punctuality D0 for KLM, per month over the period 2009 till 2014 0%# 20%# 40%# 60%# 80%# 100%#

jan.-09# nov.-09# sep.-10# jul.-11# apr.-12# feb.-13# dec.-13# okt.-14# percentage#on#-time#departures#

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One contributor to the low departure performance is the inefficient ground operation (Fricke & Schultz, 2009). Part of this ground operation are refuelling, cleaning and catering, but also the

passenger-handling process. Improving the performance of these aircraft turnaround processes

will make KLM more attractive to passengers, since a better departure performance can be achieved (Beelaerts van Blokland, Huijser, & Stahls, 2008).

It is not only inconvenient to passengers when a flight is unpunctual, it also bring major costs for airlines due to delay propagation (Eurocontrol, 2005; Wu & Caves, 2003). Aircraft that depart late will have to fly faster and burn excessively more fuel to catch up time, or connections and arrival times cannot be guaranteed anymore. In the tight schedule of the airline industry, a snowball effect in subsequent processes is easily caused and leads to high cost. Flying 5% faster may increase the fuel flow by 25% due to increased drag, assuming other variables are stable (Boeing Commercial Airplanes, 2009). The delay cost for KLM is estimated between 100 and 200 million Euro annually (Aviationexperts, 2014; Booz Allen Hamilton, 2011; Eurocontrol, 2005). Furthermore, it is not only the hard cost that is made, inter alia compensations and rebooking costs, but also soft costs like possible loss of market share (Cook, 2007). Even though delays shorter than fifteen minutes are not seen as delays in the airline industry, delays will cost an airline money: something that does not fit in the economic climate of today (Cook, 2007).

1.2 OBJECT OF STUDY AND OBJECTIVE OF THE RESEARCH

It is important to react on the situation by adjusting the aircraft turnaround operations as poor performance will lead to loss of market share and financial consequences (Groot, 2015). Besides, processes need to be safe and secure, on-time and seamless for both passengers and employees (KLM, 2014a).

Every process has an issue constraining it, at any time. These issues prevent the process from operational excellence, in this case on-time departure (Cox & Goldratt, 2009). Within KLM there is some understanding on the defects within the turnaround process, affecting the departure punctuality: these can be found all over the ground process (KLM Ground Services, 2014). The ground process is split in passenger handling and aircraft handling, as can be seen in figure

1.2. It can also be divided in above the wing only, and under the wing processes. The processes

above the wing affect the cabin of the aircraft. Other processes, such as fuelling and baggage are considered under the wing (Beelaerts van Blokland et al., 2008). The dashed line represents the border between above and under the wing processes.

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figure 1.2 Under the wing processes of passenger and aircraft handling Critical path analyses over the performance of the ground process in 2013 have shown that there are opportunities in every step of the aircraft turnaround process (KLM Ground Services, 2014). Summarizing the 17,692 cases, it can be said that the following three processes are the major disruptors part of aircraft handling:

! In 6% of all 2013 cases there is a delay due to unforseen technical issues and therefore

the plane is not available for useage

! In 17% of the cases there is a delay due to late availability of aircraft (incoming flight,

towed from a buffer location, towed from hangar after maintenance)

! In 17% of the cases the catering and / or cleaning is too late

Regarding the passenger-handling process there were some other figures raising questions. Based on data from May 2014 and November 2014 and in comparison to the set process times, it can be said that (KLM Ground Services, 2014):

! In 24% of the cases the cabin crew arrived too late at the gate

! In 36% of the cases more then 3% of the passengers were still missing at the gate at the

moment of flight closure

! In 41% of the cases the passenger doors were closed too late

! In 53% of the cases the gate process took longer than planned

All issues mentioned above can be seen as constraints for the aircraft turnaround and are eligible for improvement. However, solving them all is not possible in one single research. The choice is made for the gate process, as it may be improved the most and is at this stage the first priority to the management of KLM Passenger Services (Koopmans, 2014). The gate process is therefore the object of study.

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The gate process is the collective noun for all processes that take place at the gate area, such as the passenger door closure and boarding process that have a low performance. It is now case to find out what sub processes are in the gate process and what are the constraints preventing flights from on-time departure. The objective of this research is therefore to provide new knowledge on the gate process and its sub processes, in order to achieve more punctual departures. The development of a new method how to approach the gate process will help.

1.3 RESEARCH ORIENTATION

The research has a focus on advancing theoretical knowledge and is therefore theory-oriented (Dul & Hak, 2008, p. 34). The research is conducted from a passenger-handling perspective and uses KLM as the main source of information. Processes of airlines are in general the same: every airline has passenger-handling processes.

Most research focuses on the boarding process only, without paying attention to other gate processes in the same area or department. Boarding is often analysed for the optimal sequence as it is assumed to be the only process and bottleneck at the gate (Nyquist & McFadden, 2008; Van Landeghem & Beuselinck, 2002; Wang, 2009). A new method, also tested at KLM is the Steffen method, but this also solitarily focuses on theoretically optimizing the boarding sequence: what will work best in under laboratory conditions (Steffen, 2008). One of the few viewpoints that point in the direction of the gate process, as bottleneck in the aircraft turnaround, is that of Niehues et al. (Booz Allen Hamilton, 2011). They state the ground operations and departure process is one of three levers in the punctuality issue, and the gate process falls right in that scope. Unfortunately, only a method for assessment is given, no possible solutions.

New knowledge regarding the passenger handling process at the gate is valid given the conditions of this case and may support management of KLM Passenger Services. The theory may be generally applicable, the results and recommendations are however not tested as such.

1.4 STRUCTURE OF THE REPORT

Structure of the report follows the Case Study Methodology in Business Research by Dul and Hak (2008) and the Research Design Matrix of dr. Wouter Beelaerts van Blokland (2013). The report starts with the research background in the second chapter. This will provide more detailed information on the object of study and the scope of the research and pays attention to the main and sub research questions and research methodology that will be used. Applying the methodology gives an overview of the current state in chapter three. The desired future state will be designed in the fourth chapter, including the proposed improvements and testing on selected cases as derived from the current state.

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The fifth chapter will conclude on the research by answering the main research question and give recommendations specific for KLM regarding the bottlenecks analysed and how they can be eliminated. When during the research new bottlenecks are found, these will be mentioned for incorporation of new research (Cox & Goldratt, 2009).

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RESEARCH

BACKGROUND

CHAPTER 2

In the research background more information is provided concerning the object of study: it contains how the gate processes are designed and should look like in practice. This is needed to find the cause that makes the gate process perform substandard. The practice research is executed using document reviewing and expert interviewing. These techniques are often used together to complement each other in qualitative research and are particularly applicable to case study research to describe events, phenomena or in this case processes (Bowen, 2009). This chapter will conclude with drawing up the main research question and the methodology to be used.

2.1 PRACTICE RESEARCH

The practice research contains the scope, the gate process as specified, its performance and the capacity calculations as executed by KLM. This background information gives a good view on the object of research, to start on the same page.

2.1.1 SCOPE OF THE RESEARCH

The scope is based on interest and impact. All ground processes are required for an aircraft turnaround, but only the processes at the gate are within scope in this research. Other processes have an effect on the departure punctuality, but as they are not under control and responsibility of passenger handling they will not be analysed (Koopmans, 2014).

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I INTEREST IN SELECTED FLIGHTS

In this case intercontinental (ICA) flights are of greater interest than European (EUR) flights: on intercontinental flights the departure punctuality issues are worse: European had a 2014 on-time departure performance of 38%, where intercontinental scored only 20% (Appendix C ). Next to that, intercontinental represents a higher total passenger and cargo revenue per flight (Ottens, 2014). The focus lies therefore on the intercontinental flights, in the map below represented as orange countries outside the European network. The colours match with the gate layout in figure 2.2: intercontinental flights are handled at orange non-Schengen piers, for KLM this holds mainly pier E and F and sometimes G. D is used for smaller aircraft (European non-Schengen) and H is not used by KLM, as this pier is a low-cost pier.

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II PHYSICAL BOUNDARY

The physical boundary therefore lies where the gate process takes place: at the gates of Schiphol. The gate process takes place under the responsibility of KLM Passenger Services.

figure 2.2 Map on landside, airside processes and Schengen / Non-Schengen areas III STUDY AREA

The study area is the physical space where the object of study can be found, in this case at the gates of Schiphol. Departure gates do not always have the same layout, which makes operation different per gate. However, in general the same processes take place in the area and time and therefore this difference is neglected in this research.

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The layout in figure 2.3 is used to this research. The gate area consists of a waiting area where passengers may wait prior the opening of the gate. Two lanes provide entrance to the gate: one for priority passengers, one for economy passengers. The gate is equipped with two boarding gate readers, which is the physical equipment used to scan a boarding pass used to board the passenger. Within the gate area, accessible from both the waiting area and the gate itself, is one gate desk. At this desk the agents have their position to answer questions and solve issues using a computer. All other features not of interest for the main gate process are left out the general layout.

Airlines are not allowed to make changes in the interface as such, as a gate should be operable for all airlines. On the airport, several gates are used by KLM. They are not dedicated to any airline and not owned by any airline, but by the airport; they are common use, even though KLM is the dominant user at Schiphol (Belliotti, 2008, p. 12). This is therefore a restriction to the solution space to optimize the departure performance.

IV CENTRAL SECURITY

An important note is the change of layout that is a few months ahead: Schiphol transforms from a decentralized security terminal to a centralized security terminal. This holds that the gate has a specific clean area on its own in the current state, but in the future the whole terminal area will be a clean area. The big difference lies in the gate layout: at this moment there is a security check somewhere in the gate process (before the waiting area, between the waiting area and the gate desk or after the boarding gate readers and the gate desk). This security check is a border between the clean area and the rest of the terminal. In the future there will not be such a restriction anymore (Appendix D ).

Another big change is the relocation of all boarding gate readers. At this moment the position of the boarding gate readers is not the same for every gate. It will therefore be mentioned during the research when the position of the readers is of importance to the measurements. In the situation of central security, the boarding gate readers will all be placed as close to the jet bridge as possible, after the waiting area and the gate desk.

2.1.2 THE SPECIFIED GATE PROCESS

The specified gate process is the process as it is designed. The process below is based on information retrieved from interviews with experts of KLM and documents from their hand:

! Task description for a Gate Agent (KLM Ground Services, 2013)

! Ground Operations Manual Schiphol (KLM SPL/A3, 2011a)

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The process holds three phases with sub processes and reflects a critical path where the next phase can only be entered when all processes in the current phase are finished (Steyn, 2002). A graphic representation of the critical path of the gate process is presented in figure 2.4. Every phase and the sub processes it contains are shortly evaluated.

The security process is not a part of the gate process and not done by KLM or airlines in general. It is therefore not incorporated in the research, but dealt with as a constraining factor in the current situation. Notes are therefore made when the security process is an influence on the gate process as such.

figure 2.4 Critical path of gate process and sub processes I PREPARATION

In the preparation phase the gate team, consisting of a gate agent and service agents, arrives at the gate and start their preparations. The starting time depends on the aircraft used, but is for a Boeing 747-400 or Boeing 777-300 100 minutes prior departure. They start up all equipment, and check whether the gate is suitable for use. They also check the flight details for passengers

requiring extra attention, such as passenger with reduced mobility and unaccompanied minors,

but also passenger having a late or delayed incoming flight and have a short connection or even might miss their connection. The gate team has its own briefing, but also a briefing with the purser of the cabin crew. The cabin crew will now board and prepares the aircraft for the boarding passengers. For the cockpit crew the same is applicable.

II GATE OPEN

After the preparation phase, the gate will open to passengers. Again, starting time depends on the aircraft used, but for the Boeing 747-400 it is 90 minutes prior departure. Passengers are now invited by the agents to come forward. The gate team starts with proactively taking in hand baggage. For some flights an extra employee is available for this task, as for some flights there is more hand baggage expected than will fit in the cabin of the aircraft used.

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Preboarding starts 45 minutes prior departure. Preboarding is the process of boarding of passengers in need of assistance: passengers with reduced mobility, families travelling with infants under two years of age, unaccompanied minors and others as specified in Appendix E After the preboarding the gate team continues with general boarding. General boarding starts 40 minutes prior departure with all SkyPriority members: business class travellers, SkyTeam Elite and Elite Plus cardholders. After this group the boarding continues with all other passengers, often by blocks of seat rows, from rear to front. Besides boarding, the gate team is continuously checking the status of their flight. They watch over the ineligible to board list and the speed of boarding. If anything is wrong or uncertain, the agents have to inform their team manager.

III GATE CLOSED

Gate closure takes place fifteen minutes prior departure. No new passengers may now be accepted on board. After closing the gate, flight closure takes place. This is done ten minutes

prior departure. Normally this is done by confirming the onload of all passengers, but in case a

passenger is missing he or she and the baggage have to be offloaded before the flight can be closed. After flight closure all documents will be handed over to the cabin crew and cockpit. Two minutes prior to departure the passenger door will be closed and the jet bridge is removed. The passenger-handling process is finished and the gate can now be cleared for the next flight.

2.1.3 GATE PROCESS PERFORMANCE

The performance of departures is measured with a set performance indicators. For the departure

in general the key performance indicator is D0: departure with zero delay. This key performance

indicator is built up from performance indicators, passenger doors closed (PDC) and cargo doors closed (CDC). Passenger doors closed takes place after flight closure in the passenger-handling process, cargo doors closed after the aircraft handling process (after Baggage / Cargo): both may form the critical path. When all doors are closed, the pushback may be given when air traffic control allows doing so. In figure 2.5 the performance indicators passenger doors closed and cargo doors closed are shown, together with the air traffic control (ATC) restriction, in respect to the key performance indicator.

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Performance Indicator Target (%) Year to date result (%)

Passenger Doors Open (PDO) 70 69

Passenger Doors Closed (PDC) 48 41

All Doors Closed (ADC) 43 34

Departure Punctuality (D0) 33 20

Departure Punctuality (D15) 77 70

table 2.1 KLM Performance per indicator year to date October 1st₂₀₁₄

Part of this information is entered manually in to the computer systems and part is automatically logged. Doors open and doors closed will be logged automatically, and as such their punctuality is. This is done my means of a computerized system logger and the Aircraft Communications

Addressing and Reporting System (ACARS) (Rockwell Collins, 2015). This information is

however not yet linked to specific flights on an individual level. Therefore will this research use information available: departure punctuality per flight.

The agents enter other indicators, such as start boarding and end boarding, manually. Data integrity is compromised here, as agents have to judge on their own work. The compromise goes even further, as agents are able to backdate their proceedings. Manual logs will therefore not be used as performance indicator in the research. It can be stated that current performance is not up to standard. Regarding the data integrity it can be said that the results may be misleading, as backdating of proceedings is possible and not uncommon.

2.1.4 PLANNING OF PASSENGER-HANDLING CAPACITY AT THE GATE The number of agents in a gate team and the time they are available together determine the passenger-handling capacity at the gate. The planning of this capacity is done in five consecutive phases, as shown in figure 2.6. The first step is the highest level of aggregations, the fifth step the lowest.

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I TACTICAL PLANNING

The first step is an estimation of the total passenger-handling capacity needed for one day, responsible for the demand side. This is done with historical passenger-handling figures and

measurements. At this moment, a demand forecast is made based on time series analysis

forecasting with a constant level for service demand per passenger, in time (Chatfield, 2000). The time given is, as all types of passengers are in one category, regardless of taking in to account passenger specific characteristics. The deliverable is a schedule with the expected passenger-handling capacity needed per fifteen minutes, for a whole day.

II RESOURCE PLANNING

The second step is resource planning, responsible for the supply side. In this step the expected passenger-handling capacity needed per fifteen minutes is translated to duties of three to eight hours, to be able to plan agents of full duties with a high utilization rate. In the resource planning it is decided whom to plan and to hire per day, more than a month in advance. The final product is a long-term planning of six months in advance.

III OCCUPATION PLANNING

The third step is occupation planning. This is a fine tune step of the resource planning. Agents are now assigned to specific duties. These duties have an accuracy of fifteen minutes and also take in to account the specific needs per function: not every agent is skilled the same and may therefore not fulfil every duty.

IV ROSTERING

The fourth step is rostering. Agents will be rostered for specific tasks within their duty, taking into account their skills. This step takes place from two days up to ten hours before the day of execution. The rostering is done automatically by a computer system fed with business rules: the number of passengers on a flight, and the type of aircraft used.

V ASSIGNMENT

The fifth and last step is assignment. Assignment is quite the same as rostering, but now on the day of execution: agents already have a task assigned, but this may be changed when the operation requires doing so. Assignments will be done automatically. Disruptions such as technical delays or inbound delays due to weather and unforeseen changes are done manually, as the system is not able to cope with it.

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2.2 MAIN RESEARCH QUESTION

As an interim conclusion on the practice research it can be said that both the gate process and the allocation of capacity are standardized for all flights and passengers, which may be a potential bottleneck, as no flight or passenger is assumed the same. The standard gate process should be analysed further in order to evaluate its current design and how to improve it for the future. The main research question for the research is therefore formulated as:

What operational changes are needed regarding the gate process, in order to improve on-time passenger-handling performance?

This main research question cannot be answered immediately and is therefore split in several sub research questions. The sub research questions will be used to research a specific part, and together they will contribute answering the main research question. The five sub research questions that will be used are:

1. Why does the gate process take longer than planned? Before improvements will be suggested, it is required to understand what happens in the current state. Therefore the current state will be analyzed in depth to see what is making the gate process take longer than planned: what are the defects in the current state process?

2. What is the bottleneck in the gate process that should be improved? After the constraints have been inventorized, one is depicted the bottleneck and rest will be made subordinate. This will be the constraint with the expected largest impact.

3. What variables should be used to improve the current state gate process? Based on variables discovered in the current state, a selection will be used to determine what and how the future state should be improved, to have the gate process end on-time. These variables will also be assessed on their availability, accuracy and timeliness as this determines their usability.

4. What is the expected change in performance for the gate process? The goal is to improve the departure performance. An estimation is made on what the magnitude of the improvenent will be. An attempt is made to quantify the possible effect on the departure punctuality from an passenger-handling perspective.

5. What else is required to reach the future state? In case of a negative effect in performance as answer on sub research questions three, no further steps will be evaluated. However, in case of a positive effect it is good to know what will be needed in terms of investments, human resources or equipment.

These questions will be answered during the research when possible, finishing with answering the main research question.

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2.3 RESEARCH METHODOLOGY

To research the gate process from a passenger-handling perspective in a structured way, the case study methodology in business research by Dul and Hak (2008) is used as a guide. Where the case study research is major, parts of several other theories and tools will be used as well. This is done to present a complete and appropriate research, but also to make the situation of the gate process more tangible. Parts of other theories and tools used are:

! The Theory of Constraints

! Critical Path Anaysis

! Swim Lane Diagram

! Queuing theory

2.3.1 CASE STUDY RESEARCH

A case study is a research in which one or more cases are reviewed in their natural context and the results from this research are analysed in a qualitative manner. It has a large role in business research and is found appropriate to analyse parts of a large complex situation. When there is limited information, time and money available to conduct a full research on all aspects, a case study is more suitable as research strategy than an experiment or survey (Dul & Hak, 2008). As both conditions are true for the gate process, a case study is found suitable in this situation. By means of a comparative case study a comparison can be made between selected revealing cases. The impact of the cause to the bottleneck and later on the effect of the improvement will be evaluated. The choice for the cases to compare will be made in 4.3.3 based on qualitative and quantitative data on the punctuality of the departure in relation to the bottleneck.

2.3.2 THEORY OF CONSTRAINTS

The Theory of Constraints is a project management theory on the role of constraints. It describes the drum-buffer-rope principle (Cox & Goldratt, 2009), where the speed (drum) of the constraint determines the speed of the whole process, as they are interrelated (rope). When other processes earlier in the system go faster than the constraint, a buffer will build up and the process as a whole is suboptimal organized.

In this research the following definition is used: a process may hold several constraints, of which the one that holds up other processes is called the bottleneck. In the Theory of Constraints five consecutive steps are used to (1) identify bottlenecks, (2) decide how to exploit them, (3) make other processes subordinate to the bottleneck and (4) elevate the bottleneck. If there is now any new bottleneck (5) the process has to be repeated from the beginning (Cox & Goldratt, 2009).

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The objective of providing knowledge for a gate process leading to a punctual departure is a typical constraint problem: as during the gate process multiple processes take place and many of them are interdependent, this theory is appropriate to use (Beelaerts van Blokland et al., 2008). To find the bottleneck in the current process, interviews were held and gate process surveys were performed. These two methods are found appropriate, as they will provide a lot of information, giving a detailed view of the situation (Dul & Hak, 2008). Constraints can be equipment, human resources or policy, preventing the total gate process from an operational excellence (Rahani & al-Ashraf, 2012).

2.3.3 CRITICAL PATH ANALYSIS

Developed in the 1950s by the US navy, the critical path analysis is a non-computer approach to find logical dependencies between activities in order to determine the minimal time to spend on the whole (Fondahl, 1961; Meidan, 1981). As a project management tool, critical path analysis is commonly used in construction, maintenance, research, product development and others. The critical path analysis is used to:

! Define the activities that take place during the project, including their interrelation

! Define or estimate the length of an activity

! Define the critical path of the whole project

This will point out where in the current state process the constraints can be found (Moder, Phillips, & Davis, 1983). These processes together form the critical path as their process time defines when to enter the next process at earliest.

2.3.4 SWIM LANE DIAGRAM

A swim lane diagram is used to visualize the critical path. It can be seen as a value stream map, known from the lean philosophy (California State University, 2014). A value stream map is a diagram with “all the actions required to bring a product through the main flows essential to every product” (Rother & Shook, 1999). The swim lane diagram is a process flow chart that reveals who is doing what and what are the interdependencies in respect to other stakeholders and to time (Alphalina, 2015). This will make visual where the critical path can be found and who is working with or in it.

2.3.5 QUEUING THEORY

For planning the right amount of resources an estimation for the future demand of services and the associated service providers to produce the output within the given time frame is required (Moon, Mentzer, Smith, & Garver, 1998). For this estimation, several theories can be used, both quantitative and qualitative. Queuing theory is about waiting and one of these theories: it focuses

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on the balance between capacity and service delays (Ozcan, 2005). Queuing theory is used to determine the most effective way of operation of a queuing system (Hillier & Lieberman, 2001). The queuing system is a composition of the variables input, service and output. Customers in that system receive some kind of service from a service provider and may have to wait to receive that service: they queue (Duinkerken, 2013). Optimization systems based on this theorem are very appropriate capacity planning and capacity design tools for various industries (Smith, 2007). In figure 2.7 a basic system is shown, as this applies to airport situations as well (Neufville & Odoni, 2003). In the case of gate processes, passengers are the customers coming from the input source. The queuing system is a service mechanism represented by agents and a boarding gate reader. The queue builds up when the arrival flow of passengers is higher than the service rate of the agents. When after some while the flow of passengers becomes smaller than the service rate of the agents, the queue will shrink accordingly. The system’s output is passengers that have been serviced. This commonly accepted notation describes the arrival and service patterns and is useful as it standardizes and helps to classify the process.

figure 2.7 Scheme of a basic queuing system (Hillier & Lieberman, 2001, p. 836) Goldratt (2009) states there is a possibility of having a different process times for the different entities in the same system: in this case passengers going through the gate process. Even though the specified process is based on average service times for passenger handling, it is imaginable that in reality there are differences. Something queuing theory is capable of taking into account. The added value of queuing theory lies in the way of determining the service capacity needed with a certain service demand known by means of a small set of formulae. The counter side is the assumptions that come with queuing theory. The ignorance of human behaviour is such an example.

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ANALYSIS OF THE

CURRENT STATE

CHAPTER 3

The current state process illustrates what happens at the gate in the real context. It will answer the first sub research question: why do the gate processes take longer than planned? This is valuable as the current state is expected to differ from the specification as presented in 2.1.2 and therefore causing delays.

To report the cause of delay the IATA delay code system is used (IATA, 2015). This coding system consists of 99 prescribed reasons for delay, categorized in ten groups. The agent logs the reason for any delay caused at the end of her shift. However, the data logged does not correspond to the actual delays caused: information retrieved from visual inspections was different than what was entered in the system. The delay codes are therefore seen as unusable and will not be included in further research (Appendix F ).

The analysis of the current state will be executed according to the Theory of Constraints, as is found applicable in 1.4. The gate process is rewritten to a queuing system and for the identification of constraints, the first step op the Theory of Constraints. A critical path analysis is done to check what sub processes form constraints in the gate process (Steyn, 2002). This will

help answering the second sub question: what is the bottleneck in the gate process that should be

improved? The critical path analysis consists of a survey carried out on the sub processes as presented in figure 2.4. The results are shown in a swim lane diagram: this is useful to understand the interrelation and see where in the process defects pop-up.

By means of surveying, the process is viewed in its real life context, while scores from these observations may be analysed in a quantitative manner (Dul & Hak, 2008). This is valuable in particular, as this will address the problem quantitatively. Quantitative analyses are executed on actual data. The results of the analysis of the current state will lead to the choice of the

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bottleneck in the gate process. Due to its size, the full diagram can be found in Appendix G , but a partial cut out is presented in figure 3.1. This first cut out is a passenger with a request at the gate. What can be seen is the process of a passenger having a request to the Gate Agent or Service Agent. They try to solve the issue and if possible add value to the process of the passenger. If not, the maximum value of the flight for that passenger will not be met.

Passenger

Gate Agent

Service Agent

figure 3.1 Part of the of swim lane diagram The main findings of the complete swim lane diagram are clustered and discussed in this chapter.

3.1 GATE PROCESS AS QUEUING SYSTEM

The gate process is in principle a queuing system: passengers arrive in the system to receive a service and sometimes have to wait before they will receive the service: they queue. The gate process, as represented in figure 3.2 will be evaluated to determine what are the interrelations in the system.

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figure 3.2 Gate queuing system For passengers, the gate process is about waiting and about boarding the aircraft. For an airline, it is much more, although most literature only focuses on the boarding sequence or platform processes. The gate process will be described as a queuing process in four parts, but their interrelations however are far more interesting. At the bottom of figure 3.2 two times are displayed, the turn around time and the gate process time. The first is given by the network planning: the aircraft is for a certain time at the airport and must inter alia be cleaned, catered and fuelled. In this turn around time, a certain share of time is available for the gate process: the gate process time. The gate process time is assumed fixed as well, but it is dependent on other turn around processes, due to network planning as mentioned.

I INPUT SOURCE

The input sources for gate processes are all possibilities where passenger may come from. This can be from home, local passengers, or from an inbound flight, transfer passengers.

II QUEUING AREA

Agents facilitate the gate process. There is a certain service capacity assigned, as mentioned in figure 2.6 based on the number of passengers on a flight. When agents are busy and not directly available to a new passenger, the passenger has to wait until serviced. This queuing is done in the queuing area.

III SERVICE PROCESS

In the third block passengers receive service. This can be service on demand, such as asking a question, or obligatory service, such as scanning the boarding pass before boarding. When servicing has finished, passengers leave the gate and usually board the aircraft. It may also be the case they asked for service prior boarding. In the latter case passengers go back to the gate area, before queuing again for the boarding process.

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In this system, the passengers determine the service demand and the supply of agents determine the service capacity. They must be in balance. If this balance is not achieved due to low service capacity, the queue will build up. The queue as such is not an issue, but it also means the process will take longer, as every passenger in the queue still has to be served and there is no balking or

reneging involved in the departure process (Hillier & Lieberman, 2001). When the new demand

becomes smaller than the service capacity, the backlog in the queue is eliminated. The total time

available for servicing, including any backlog, is the gate process time as mentioned. When this time is exceeded, the performance is substandard and the gate process becomes a constraint in the departure process. It is now case to check the current state on the aspects in the gate queuing system to find the constraints.

3.2 ARRIVAL OF PASSENGERS

With the arrival of passengers there are three variables that will be discussed:

! Number of passengers

! Passenger arrival pattern

! Passenger type

3.2.1 NUMBER OF PASSENGERS

For every flight a maximum number of passengers can be expected; the calling population is finite. The number of passengers that will arrive is known in advance, as can be seen in figure 3.3. The number of booked tickets is a good predictor of the number of passengers that can be expected at the gate. There will always be some no-shows, as passengers may rebook their ticket, miss their flight or have another reason to not show up, but this is last moment information and is only a small percentage (Lawrence, Hong, & Cherrier, 2003).

figure 3.3 Booked load factor in days before departure (January till December 2014) (KLM Pricing & Revenue Management, 2015a) 0%# 20%# 40%# 60%# 80%# 100%# time#to#departure#(days)# booked#load#factor#

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3.2.2 PASSENGER ARRIVAL PATTERN

It is assumed passengers can be classified in two groups according to their arrival pattern.

! Transfer: passengers whom have a transfer at Schiphol, but originate from another airport (KLM and non-KLM network)

! Local: passengers whom originate from Amsterdam Airport Schiphol

The passenger arrival pattern in the current capacity calculation assumed to be uniformly distributed: every fixed time interval a new passenger arrives at the gate. Surveys have shown this is not the case: passengers tend to come when they like to. Their arrival pattern is therefore memoryless and independent of precedent arrivals (Duinkerken, 2013). Most passengers turn up in time, but not at set times. Some passengers arrive at the gate alone, some in groups of over twenty. In order to determine the influences on the arrival pattern, the following is checked with passenger data: their connection times at the airport, influence of time of day, actual inter arrival time and pattern.

I CONNECTIONS

Short connections are often referred to as cause for delay: in order to board all passengers, they should be at the gate in time. Connection times are crucial, as a short connection may entail that the passenger runs in late. However, the data in figure 3.4 and figure 3.5 show that most passengers have plenty of time for their transfer, as they have a minimum of 50 minutes of transfer time.

figure 3.4 Time between actual time of arrival and scheduled time of departure in January 2014 0# 400# 800# 1200# 1600# 2000# 2400# 2800# time#to#departure#(minutes)# passengers#

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figure 3.5 Time between actual time of arrival and scheduled time of departure in February 2014

figure 3.6 Moment of boarding till scheduled time of departure in January 2014

figure 3.7 Passengers per time frame of minutes: moment of boarding till scheduled time of departure in February 2014 0# 400# 800# 1200# 1600# 2000# 2400# 2800# time#to#departure#(minutes)# passengers# 0# 200# 400# 600# 800# 1000# 1200# time#to#departure#(minutes)# passengers# 0# 200# 400# 600# 800# 1000# 1200# time#to#departure#(minutes)# passengers#

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Knowledge on the inbound flights is valuable for the departure process: as it is not specifically known when passengers turn up, inbound flight data can be used to forecast when passengers will not be at the gate. Their earliest time to show up at the gate is the actual time of arrival of their inbound flight, plus the minimum time to walk and, in case needed, passport control and security.

Late passengers may disturb the process, as is the bar most right in figure 3.6 and figure 3.7, as they potentially need some additional servicing as well. Especially groups are problematic here: large groups arriving at once disturb the arrival process and build a queue and a backlog is establishing. Popular connections are inter alia:

From To (via Amsterdam) Issue Passengers/year

London LHR, UK Accra ACC, Ghana Hand baggage 11,600

Milan LIN, Italy Guayaquil GYE, Ecuador Short connection 9,800

Milan LIN, Italy Lima LIM, Peru Short connection 7,000

Barcelona BCN, Spain Guayaquil GYE, Ecuador Short connection 6,700

Detroit DTW, USA New Delhi DEL, India Reduced mobility 6,200

table 3.1 Top5 KLM connections AMS outbound for 2014 often causing issues (KLM Pricing & Revenue Management, 2015b)

As can be derived from table 3.1, there are on average 27 passengers per day from Milan, Italy and eighteen from Barcelona, Spain that head for the daily flight to Guayaquil, Colombia. This is already 15% of the aircraft (Boeing 777-200ER, 318 seats). These passengers often arrive with a short connection (1h20m and 1h15m respectively) and turn op at the gate close to flight closure: these 80 minutes should be used for disembarking the aircraft, passport control, security and walking in between, while the flight closure starts at twenty minutes to departure, leaving just an hour. It is possible, as the minimum connection time at Schiphol is 50 minutes, but one should anticipate on 45 passengers per flight arriving relatively late.

II TIME OF DAY

Local passengers have an arrival pattern that is independent of other flights. According to Neufville and Odoni (2003) the time of day has an influence on the arrival pattern of these passengers: early flights tend to have a steeper arrival pattern as passengers tend to rise as late as possible, whereas for afternoon flights they tend to be as early as possible at the airport, sometime for over three hours.

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figure 3.8 Arrival pattern at the airport differs per time of day (Neufville & Odoni, 2003) During the surveys this influence has not been incorporated as variable, as the earliest intercontinental flight departs at 08.40 hours and the second at 09.50 hours. The first flight heads to Sint Maarten in the Caribbean, which is not a flight with transfer passengers, but a point-to-point destination. The impact of delay is relatively small: there are few onward connections and at Sint Maarten the aircraft has a relative long ground time, forgiving small arrival delays.

III ACTUAL INTER ARRIVAL TIME AND PATTERN

The arrival pattern of passengers at the gate is of importance, as it will determine the resource capacity you will need at some point. However, it has never been measured before. There is information available on the arrival of local passengers at Schiphol and on the arrival of transfer passengers by the incoming flight, but this figure can not directly be used as arrival rate: it is moderated by processes that take place in between, such as shopping and drinking a coffee (Neufville & Odoni, 2003). Therefore, this data is not accurate anymore for the arrival at the gate. This distribution pattern is often much steeper: this can be derived from figure 3.4 until figure 3.7 as well. Passengers have a certain connection time, but do not spend it at the gate, but somewhere else in the terminal or, in case of an overnight stay, even outside the terminal area.

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In the current state, which is the process as it is executed today, the arrival pattern at the gate shows an exponential distribution: inter arrival times lie mainly between zero and sixty seconds, as can be seen in figure 3.10. This pattern matches the distributions as described by Neufville and Odoni (2003): passengers arrive in a steep curve.

figure 3.10 Distribution of the inter arrival time for four flights (blue: Accra, orange: Paramaribo, grey: Tokyo, black: Manila)

The coefficient of determination (R2_{) determines whether the data fits the projected curve: the}

exponential curve. R2_{is in all cases relatively high and therefore confirm the expectations: the} inter arrival times are exponentially distributed. Measurements for the four distributions patterns above are obtained from personal observations. Measurements were started 100 minutes prior departure and lasted till ten minutes prior departure: flight closure. The security process is of influence here: at this moment the security process may influence the arrival gate when it takes place in front of the queue and therefore the gate opens early.

Passengers already around the gate of departure where counted as direct arrivals with no inter arrival time. The arrival rate, on average, can be determined by dividing the calling population by the time observed. For Accra, Paramaribo, Tokyo and Manila these are 1.80, 4.19, 4.34 and 4.24 passengers per minute respectively, on average, following an exponential distribution of their inter-arrival time. R²#=#0,88782# 0# 10# 20# 30# 40# 50# 60# time#(mm:ss)# passengers# R²#=#0,94844# 0# 50# 100# 150# 200# 250# time#(mm:ss)# passengers# R²#=#0,94033# 0# 50# 100# 150# 200# 250# time#(mm:ss)# passengers# R²#=#0,94624# 0# 50# 100# 150# 200# 250# time#(mm:ss)# passengers#

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3.2.3 PASSENGER TYPE

During the arrival, passengers from different service types may be distinguished already: priority passengers, such as business class travellers, elite frequent flyer card holders and passengers with reduced mobility, enter the gate area via the priority lane and other passengers via the regular lane. There is no clear evidence on what passenger arrives at the gate first. There is no clear arrival pattern for business or leisure travellers: when the gate process start, frequent flyers (by frequent flyer status) are equally spread. As can be derived from figure 3.11 till figure 3.13, the frequent flyer passengers (red diamonds) do not turn up later than economy passengers.

figure 3.11 Arrival pattern at gate for frequent flyers (red), other passengers (orange) and totals (blue) on a flight to Shanghai, day 1

figure 3.12 Arrival pattern at gate for frequent flyers (red), other passengers (orange) and totals (blue) on a flight to Shanghai, day 2 0# 5# 10# 15# 20# 25# 30# 0:00# 0:15# 0:30# 0:45# 1:00# 1:15# 1:30# time#(h:mm)# passengers# 0# 5# 10# 15# 20# 25# 30# 0:00# 0:15# 0:30# 0:45# 1:00# 1:15# 1:30# time#(h:mm)# passengers#

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figure 3.13 Arrival pattern at gate for frequent flyers (red), other passengers (orange) and totals (blue) on a flight to Shanghai, day 3 The black lines in the figures show a two period average of the dots: the upper line for the orange dots, the lower for the red dots. Measurements are taken in time frames of five minutes to give a precise view.

3.3 QUEUING OF PASSENGERS

The queue is most often referred to as a waiting line. It is where passengers have to wait upon they will be serviced. This occurs when the input is higher than the maximum of passengers that can be serviced within a certain time frame.

3.3.1 WAITING

The waiting mainly holds for passengers: most of their time they spend waiting in the gate area. This might be due to stepwise approach of the boarding process, but also when there are questions, issues or checks. Often the pace of employees is too low for the demand, or the inventory was built up too large.

3.3.2 QUEUE CAPACITY

The capacity of the queue is infinite, and therewith the system as well. There is no limit in number of passenger that may enter the queue, although it might give issues in the physical space available. In practice, the number of passengers in the queue will not exceed the total number of passengers expected (Hillier & Lieberman, 2001).

3.3.3 QUEUE DISCIPLINE

The queue discipline determines what input is going to be processed first. In case of the gate process, this is service according to priority (Hillier & Lieberman, 2001).

0# 5# 10# 15# 20# 25# 30# 0:00# 0:15# 0:30# 0:45# 1:00# 1:15# 1:30# time#(h:mm)# passengers#

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3.4 PASSENGER SERVICE MECHANISM

The service mechanism is the combination of service equipment and servers: personnel. At

airlines the service equipment is the combination of a boarding gate reader and a computer. The

server is the agent. Together they form the service mechanism at the gate. Within the passenger service mechanism the following four topics of interest can be found:

! Number of processes

! Service speed

! Waiting

! Service capacity

3.4.1 NUMBER OF PROCESSES

Compared to the process specification of agents, the actual situation holds more sub processes. These sub processes tend to go parallel instead of serial. All sub processes carried out in the second phase of the gate process (figure 2.4) are eligible for becoming the constraint preventing continuation of the process within time available.

figure 3.14 More processes in the current state than specified Four examples are given of sub processes that are often found in the current state.

I DATA INTEGRITY

Data integrity is on the validity of all data in the system, compared to the customer’s situation. Boarding gate readers are the physical installations at the gate that are able to scan the boarding pass. When a boarding pass is scanned, the boarding gate readers sends data of that boarding pass to the departure control system, where the boarding pass is compared to the information in the database. Here the match is made between the booking and the boarding pass. The match is found OK when a passenger has fulfilled all requirements needed for his specific seat and destination. However, some passengers arriving at the gate may still have an issue with their booking. Issues that occur often, if not every flight for several times are:

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! Incomplete passport information

! Incomplete Advanced passenger information (API)

! Incorrent seat on the boarding pass

! Safety check for exit doors seats

In case all data is OK, a green light appears and a high beep sounds. It is however the case that no flight has a 100% score on data integrity: there is always at least one issue. It would be very interesting to have the data of the number of defects per flight and the specification of the error, as it expected to have a large impact and gives perfect clarity on what problems occur when and where. Unfortunately, the data found cannot be used yet, as there is no reader for the files. The location of the boarding gate readers is in this case of importance: the earlier a passenger with any issue is identified, the earlier issues can be resolved.

II QUESTIONS AND REQUESTS

Where the specification assumes a perfect process, the current state holds many questions and requests of passengers. Examples of these questions and requests are:

! Seat changes

! Standby

! Airline staff travel

! Time of arrival

! Terminal of arrival

These questions take time. Although it is not of primary interest to KLM, not specified and non-value adding, these are questions and requests the gate team deals with, in the time prior to the boarding process. The occurrence of this process is often: for every flight questions are asked and requests are made.

III OVERBOOKINGS

One of the defects costing a lot of time is overbooking. Every airline in principle sells more seats than available (Lawrence et al., 2003). In most cases, this issue solves itself as not all tickets are sold, or not all passengers turn up. However, in some cases there will be more passengers checked-in than seats available. This generates a lot of extra work as a certain percentage of passengers receive a standby boarding pass without seat number: seats have to be assigned manually short before departure. The occurrence of this process is regular, and when it happens it takes quite some time.

IV TAKING IN HAND BAGGAGE

For some flights it is still needed to take in hand baggage, as more baggage is brought to the gate than will fit in the aircraft. There are two main causes for this issue: the first one is the digitizing of airline business. For passengers that check-in at home and head towards the aircraft, the gate

TOWARDS ON-TIME PASSENGER HANDLING - CASE STUDY RESEARCH ON THE REQUIRED SERVICE CAPACITY FOR AN ON-TIME PASSENGER-HANDLING PROCESS AT THE GATE